In a conventional X-Y travelling table, a pair of monoaxial moving mechanisms, each of which is composed of a pair of straight motion guide bearings and one feed screw mechanism to provide movement in one direction, are mounted in combination with their moving directions kept orthogonal to cause a table to move lengthwise and crosswise.
Such a structure has various problems, such as that the height from the support base to the table is sufficiently great to make the mechanism relatively unstable and to cause it to occupy a large space, that the number of parts is large, that many man hours are required for assembling, that it is relatively difficult to assembly with accuracy, and so on.